Electric switch with improved toggle mounting means



0 United States Patent [1113,546,412

[7 21 Inventor Carlton E. Sanford [56] References Cited Riverside, M 519ml UNITED STATES PATENTS 2 g- 22% 1968 3,248,511 4/1966 Heilman ..200/l68G(UX) 9 Patented Dec. 1970 3,1? 16,378 4ll967 Ryan ...200/l68G(UX) [73] Assignee Texas In trument In o ted Prrmary Examiner-Robert K. Schaefer Dallas, Texas Assistant Examiner-D. Smith, Jr. a corporation of Del w r Attorneys-Harold Levine, Edward J. Connors, Jr. John A,

Hang and James P. McAndrews [541 ELECTRIC SWITCH WITH IMPROVED TOGGLE MOUNTING MEANS 10 Claims 5 Drawing Figs ABSTRACT: An electric switch having a conventional toggle [52] US. Cl. 200/168, mechanism mounted in an improved yoke which is drawn 200/67, 200/68 from flat stock metal and shaped in such a way to provide the [51] Int. Cl. HOlh 9/04 required structural strength and rigidity. in one embodiment, [50] Field of Search ..200/67.67(A), the yoke structure forms the cover of the switch while in another it is mounted on a conventional cover member.

PATENTEU DEC 8 I970 SHEET 2 BF 2 INVENTOR, a rZton ESanford,

Attjl.

ELECTRIC SWITCH WITH IMPROVED TOGGLE MOUNTING'MEANS This invention relates to electrical switches in which a toggle is used to actuate the switch and, more particularly, to the support mechanism employed. for mounting the toggle. Switches of this general type are known in the art, for example, as described and claimed in coassigned U.S. Pat. No. 3,322,914 issued May 30, 1967 to Puccini. In such switches an actuator is attached to oneend. of the toggle in such a manner that pivotal movement of the actuator will cause movement of a movable contact arm in a contacts opening or closing direction. The toggle is mounted in a support structure or yoke of a type which facilitates hermetic sealing of the switch and which must be relatively strong to withstand not only the actuation force required for switching but also any accidental or excessive forces applied to the switch. To obtain maximum strength, the yokes in prior art devices were fashioned out of a solid block of material requiring a plurality of machining operations. The yoke therefore constituted a major expense of the switch and a limiting factor for use of the switch, due to the high costs occasioned by the machining operations. Further, this relatively massive yoke adds significantly to the total weight of the switch thereby further limiting the switchs usefulness in some applications, such as in space modules, airplanes and the like, where every increment of weight is considered to be critical.

In view of the limitations of the prior'art structures mentioned above, it is an object of this invention to provide a yoke which is significantly less expensive to manufacture, lighter in weight while still retaining suflicient strength and the structural integrity of the former yoke.

Another object is the provision of a toggle switch yoke which permits economical hermetic assemblage of the switch elements.

The invention accordingly comprises the elements and combination of elements, features of construction, and arrangement of parts which will be exemplified in the construction hereafter described, and-the'scope of which will be indicated in the appended claims.

In the drawings, in which several of the various possible embodiments of the invention is illustrated,

FIG. 1 is a cross section view of a switch showing a yoke partly in cross section and constructed in accordance with the invention;

FIG. 2 is a perspective view of the yoke shown in FIG. 1;

FIG. 3 is a perspective view of a prior art yoke;

FIG. 4 is a partial cross-sectioned view of a second embodiment of the invention; and Q FIG. 5 is a perspective view of the yoke shown in FIG. 4.

Similar reference characters indicate corresponding parts I throughout the views of the drawings. Dimensions of certain of the parts as shown in the accompanying drawings have been modified for the purpose of clarity of illustration. I

Referring now to the drawings, particularly FIGS. 1-3, an exemplary construction is shown which takes the form of a three-position, snap-action toggle switch generally indicated by reference numeral 10. It will be understood that the yoke structure of this invention can be used with any switch which employs a pivotably mounted toggle member, particularly when it is desirable to hermetically seal the toggle mechanism.

Casing 12 is generally a rectangular parallel piped in shape and formed of a conventional metal which can be bent and welded, such as cold roll steel. Casing 12 is formed with an outwardly extending flange 14 on the upper end thereof and an inwardly extending flange 16cm the lower end thereof. A base 18 rests on inwardly extending flange 16 of casing 12 and is hermetically attached thereto as indicated by weld 20.

dicated at 32 and is provided with an aperture 34 through which is inserted sleeve 36 having a'radially outwardly extending flange 40 which is hermetically attached to cover 30 in a conventional manner as by welding at 42. Switch 10 may be conveniently mounted by 'means of threaded portion 38 of sleeve 36 to a suitable support structure (not shown). Sleeve 36 also serves to protect the bellows mechanism contained therein from accidental blows from foreign objects, gross contaminants, and the like. Attached as by welding at 84 to the bottom surface of flange 40 is outwardly radially extending flange 82 of yoke 80. Bellows 44 is attached in a conventional manner intermediate the inner periphery of sleeve 36 and yoke at one end and to toggle 46'at the other end, as by soldering. Bellows 44 is constructed of a thin, resilient tubular material such as nickel. A flexible gasket of conventional material, such as rubber, is placed in the top portion of sleeve 36 around toggle 46 to exclude from the bellows area gross contaminants such as dirt, grit, and so on.

Toggle 46 is pivotably mounted in yoke 80 by pin 50 and is attached to toggle block 52 which in turn slidably mounts actuator member 54 which is biased outwardly by a conventional spring (not. shown). Actuator member 54 mounts between bifurcation 56 an actuator roll 58 which, if desired to minimize friction losses, can be composed of a self-lubricating material such as an oil-impregnated material. Actuator roll 58 serves to transmit force from the toggle 46 to-stiff actuator plate 60 and flexible movable contact arm 62 and is formed with a V-shaped portion intermediate its ends and overlays distal portions 64 of a Ushaped electrically conductive frame member 66 connected to terminal 28. Movable contact arm 62 has located on opposite ends thereof movable contacts 70a, 70b which are adapted to move into and out of engagement with stationary contacts 72a, 72b respectively. It will be seen that pivotal movement of toggle member 46 in a counter clockwise direction from the neutral open contact position shown in FIG. 1, will cause'actuator roll 58 to ride up the V- shaped portion of actuator plate 60 until the extended line of force acting through roll 58 passes outside of the U-shaped frame 66, causing plate 60 to move downwardly which in turn causes movable contact 70b to engage stationary contact 72b. In like manner, clockwise movement of toggle 46 will cause to the center position will cause opening of contacts 70b, 72b. Further, clockwise movement of toggle 46 will cause movable contact 70a to engage 72a.

The yoke employed in the structure shown in U.S. Pat. No. 3,322,914 referred to supra, is shown in FIG. 3 and is formed from a solid, round stainless steel rod through multiple machining operations, including turning down of body portion from outside diameter 102 with weld projection 104 formed on the distal portion of the resulting flange 106. Fortions 108, are formed in the shape of a frustum of a cone by further machining and then cylindrical section 112 is formed. End 114 is preferably rounded, and bore 116 drilled and countersunk. The yoke is bored to define cavity 118 and lastly cross cut as by milling to provide ,bifurcations 120, 122 between which is mounted the toggle member. It is apparent from the above description that this is an element of relatively very high cost due primarily to the cost of machining which was necessitated by the requirement of providing a mount which is strong enough to withstand the forces applied through the toggle element. It is also apparent that this member is a relatively massive, heavy piece, yet a very substantial portion of the starting material is reduced to-scrap chips through the machining operations.

In order to obviate this problem while still maintaining sufficient structural integrity so that forces applied through the toggle would not deleteriously affect the yoke, and to permit a low cost element so that the overall cost of the switch could be materially reduced as well as the overall weight, the invention provides an improved yoke 80, see FIG. 2, constructed out of a flat piece of stock, such as SAE 304 stainless steel plate. Not

a only must the structural strength be maintained, but provision must be made for egress of corrosive residues formed upon soldering of the bellows to yoke 80. The flat piece of stock is drawn into a cylindrical portion 86 and then into a portion having opposed generally triangular-shaped sidewalls 88 generally parallel to each other and joined by a flat web 90 on two of the three triangle legs. A shelf 92 is formed and apertu res 94 and 98 are pierced, the former to permit egress of waste material during the soldering operation, and the latter to provide access for toggle 46. The drawing operation per se is known in the metal forming art and need not be further explained here. The outer periphery of flange 82 is bent on approximately a 45 angle to provide weld projection 85 and finally bore 97 is drilled and countersunk.

A yoke made as described above has been tested and found tohave the required structural strength and rigidity. Specifically, though the walls of a yoke 80 made as described above were formed with a thickness of 0.02 inches when subjected to a 25 -pound static load appl ed at right angles to toggle 46 approximately 0.66 inches from pin 50 for 1 minute, there was no permanent deformation.

While the prior art yoke 99 also has sufficient structural strength with a flange 106 of 0.02 inches bifurcations 120, 122 were as thick as 0.117 inches at the thickest point, or almost six times as thick as the wall thickness of yoke 80. Use of yoke 80 also results in a great savings in time due to the drawing techniques and with virtually no wasted material. The particular shape of the structure of yoke 80 provides the necessary strength while employing a minimal amount of material and further provides egress for waste material through apertures 94. This waste material, if allowed to stay within the switch, would materially affect the useful like of the switch since it is corrosive in nature.

It is also possible to form sleeve 36 without radial flange 40, or with a reduced flange40, by hermetically attaching flange 82 of yoke 80 directly to cover 30 of the switch casing.

A second embodiment is shown in FIGS. 4 and 5 in which outwardly radially extending flange 200 formed integrally with cylindrical body portion 204 of the yoke serves as the cover of the switch casing, thereby further simplifying the switch structures. A plurality of radially extending grooves or deformations are provided in flange 200 to enhance its structural rigidity. The remainder of the yoke is identical to that of the FIG. 2 embodiment, including the triangular walls 208, web 210 joining two of the three wall legs and apertures 206, 212 to provide egress of waste material and to permit reception of arm 46 respectively. Sleeve 222 is formed without a radial flange and is attached to flange 200, as by welding. Flange 200 is hermetically attached directly to flange 14 of casing 12, as by welding. As in the FIG. 1 embodiment, sleeve 222 is threaded at 224 to facilitate mounting of the switch in a controlpanel. A bellows 216 hermetically seals the switch around the't'oggle mount and has an end 214 intermediate sleeve 222 and cylindrical body portion 204 of the yoke and another end attached to the toggle arm 46 beyond the pivotal mount. The bellows is hermetically attached to the yoke and toggle as by soldering. I

The embodiment of FIGS. 4 and 5 in effect results in structureeven more simplified than that shown in FIGS. 1 and 2, withconcomitant savings without sacrificing performance in anyway.

Thus, it will be seen that the several objects of the invention are achieved and other advantageous results obtained.

It,is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways.

Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompan ing-drawings, shall be interpreted as illustrative and not in a imitmg sense, and it IS also intended that the appended claims shall cover all such equivalent variations as come within the true spirit and scope of the invention.

. IClaimi I 1. An electrical switch having a casing which includes a toggle pivotably mounted in a yoke attached to the casing, the yoke comprising:

a cylindrical body portion having two ends;

two flat, generally triangular sidewalls, each having a first and second leg and a base leg opposite an apex, two webs joining the two sidewalls, one web joining the two first legs of the triangular walls short of the apex, the second web joining the two second legs of the triangular walls short of the apex, both webs integral with one end of the cylindrical body portion; and

the base of each triangular wall being detached from the cylindrical body portion, the end of the body portion adjacent the base leg of the triangular walls turned inwardly and defining with the base leg of each triangular wall an aperture, a bore formed in the apex of each triangle wall, and an outwardly radially extending flange integral with the other end of the cylindrical body portion.

2. A switch according to claim 1 in which the triangular sidewalls generally lie in planes parallel to one another.

3. A switch according to claim 1 in which the outer periphery of the outwardly, radially extending flangeis bent out of the plane of the flange to form a weld projection for attachment of the yoke to the switch casing.

4. A switch according to claim 1 in which the outwardly radially extending flange forms a cover for the switch and is welded thereto. 7 I

5. A switch according to claim 4 in which a plurality of deformations are formed in the flange to enhance its rigidity.

6. A switch according to claimSin which the deformations extend radially.

7. A switch according to claim 3 further including a cylindrical sleeve, an outwardly radially extending flange formed integrally with one end of the sleeve, the yoke telescopically received in the sleeve with the flange of the sleeve alined with and hermetically attached to the flange of the yoke, the flange of the sleeve in turn hermetically attached to the switch casing.

8. A switch according to claim 7 which includes a toggle element pivotably mounted in the yoke, a bellows member having two ends, one end circumscribing the cylindrical body portion of the yoke intermediate the yoke and sleeve member, the other end circumscribing the toggle element to enclose the pivotal mount of the toggle.

9. A switch according to claim 4 further including a cylindrical sleeve placed over the yoke and attached to the yoke flange, a toggle element pivotably mounted in the yoke, a bellows member having two ends, one end circumscribing the cylindrical body portion of the yoke intermediate the yoke and sleeve member, the other end circumscribing the toggle ,element to enclose the pivotal.

10. An electrical switch having a casingwliich includes a toggle pivotably mounted in a yoke attached'to the casing, the

yokecomprisingz' La first section generally cylindrical antl'li'aving two ends; and

second section integrally attached tofone end of the first section, the second section having two triangular walls,

each wall having a first and second'leg and a base leg opposite an apex, the first'and second legs of one triangular triangular wall respectively, an aperture in the yoke formed adjacent each base leg to permit egress of gaseous material from the switch casing, and an aperture formed near each apexfor pivotal mounting of the toggle, the wall forming the cylindrical first section and the walls of the second section of approximate uniform thickness throughout;

" wall connected to the first and second legs'of the other 

